Swimming pools and spas enjoy widespread popularity in many parts of the world. Such pools and spas are built in a wide variety of shapes, and with a number of different construction techniques. The most expensive installations, and the ones considered the most aesthetically appealing, are "in-ground" pools. Such pools first require an excavation to be made in the rough dimensions of the pool. Following the initial excavation of the hole in which the pool is to be placed, different steps are taken, depending upon the particular type of pool construction which is to be employed.
The two most common types of in-ground pools have interior finishes made of either a masonry type finish, plaster, marcite, exposed aggregate, etc. or a vinyl liner finish.
The masonry finished pool has, historically had advantages over the vinyl lined pool in aesthetics and ease of cleaning. All pools have inlets and outlets to facilitate the circulation and cleaning of the pool. In a masonry finished pool, these inlets can be installed flush with the interior surface of the pool because the masonry finish seals against the outside of the fittings. In contrast, the vinyl fittings must clamp the vinyl liner material to facilitate sealing. Typically, this clamping required a part to be installed on the surface of the liner, which stands off the interior surface of the pool. These fittings typically are made of white plastic and held in place by steel screws, all of which increase the visibility of the fittings. In addition to the visibility problem, the part standing above the interior surface tends to catch debris and pose an obstacle to swimmers and robotic cleaning devices. These problems give vinyl pools a perceived lesser value compared to masonry pools with flush mounted fittings.
In the installation of a vinyl liner for a swimming pool or spa, the liner has no pre-formed openings in it. Consequently, when it is in place it covers the drain, returns, cleaning fitting openings, skimmer openings, etc. As a result, it is necessary to secure the vinyl liner around these openings and then cut the liner in appropriate shapes for each of the different inlets or outlets to the pool, which ultimately will be beneath the water level of the pool when it is filled.
In typical installations, prior to the water level reaching the various openings in the pool, a face plate first is secured to the fitting, which projects a short distance beyond the pool wall after the vinyl is stretched in place over the fitting opening. Because the vinyl is under considerable tension over many of these openings, it is not possible to cut a hole in the vinyl first and then apply a securing face plate over the opening. The attachment of the face plate or cap over each of the openings must be made while the vinyl is still stretched across the opening. Typically, this is accomplished by first placing a gasket around the short projection of the fitting or pipe (either under or over the vinyl). The face plate then is screwed into mating holes in the fitting behind the vinyl to secure everything in place. The result is that the face plate extends or projects into the pool, out from the surface (wall or bottom) of the vinyl. Although the projection of the face plate, which secures the vinyl to the fitting, is not significant, it can extend up to one-half inch beyond the vinyl wall or floor, particularly in the case of floor drain face plate securing rings.
Typical face plates are attached to the fittings by screwing the face plate into mating holes in the fitting behind the vinyl to secure everything in place. The screws (usually four or more) are driven through the vinyl into the holes behind it in the fitting to secure the face plate, a gasket (if one is used), vinyl and fitting together in a clamped sandwich. After the face plate has been secured, a sharp knife or razor blade is used to cut the vinyl liner material from inside the face plate; so that the opening is completed through the face plate to the communicating plumbing attached to the fitting. It is important that the screws are tightenned securely and evenly to prevent any subsequent leak of the water from the pool around the fitting and behind the vinyl and/or the pool wall or floor.
An improvement in fitting assemblies for vinyl lined pools is disclosed in U.S. Pat. No. 4,561,134 to Mathews et al. In the Mathews patent, the face plate is not secured by means of screws, but includes a fitting member with a flange on it for engaging the wall surface around the opening on the inside of the pool. The flange has a set of notches or keys in it for facilitating alignment of a face plate cap, which in turn has an opening through it, designed to align with a corresponding opening through the fitting member. The face plate cap is pressed toward the flange on the fitting member, and is located by mating projections or depressions, which align with the notches or keys on the flange to hold it in place. The vinyl liner in the opening then is cut away and a final retaining ring is threaded into the threaded interior of the fitting to press the face plate into tight engagement with the vinyl and the flange on the fitting member to hold everything in place. The fitting assembly of this patent, however, still has the face plate cap extending out into the pool beyond the wall surface formed by the vinyl liner. This protrusion may be contacted by swimmers or persons using the pool, and also permits dirt deposits to be formed around it.
It is desirable to provide an effective, simple, flush mounted installation of face plates for fittings in vinyl pool constructions.